“People have become stressed and anxious about not getting what they perceive to be the perfect night’s sleep,” says Dr Guy Leschziner, a consultant neurologist at Guy’s Hospital in south London.

“Some become so obsessed with their sleep that they generate insomnia.”

It’s extreme cases such as this, in addition to rare and more serious afflictions, that Dr Leschziner and his team of neurologists, sleep technicians and nurses deal with each year.

Between 13,000 and 14,000 patients are referred to the Sleep Disorders Centre annually, of which 3,000 are admitted for polysomnography – known as a sleep study. Typically, sensors are attached to a patient’s face and neck to monitor eye movement and brain activity.

Some may be fitted with wires and bands to track their position, pulse and leg movements.

A Continuous Positive Airway Pressure (CPAP) mask is worn by some to treat obstructive sleep apnoea, a common condition where the walls of the throat narrow and interrupt normal breathing during sleep.

More people coming forward

Once attached to various monitors, wires are fed through the ceiling of the nine-bed unit to an office, where the team analyses the patient’s slumber.

The Guy’s Hospital sleep clinic used 3,000 patients for an overnight study last year – up 7.6 per cent on the year to April 2015, when 2,787 patients were referred.

Dr Leschziner, 44, says it’s hard to pinpoint trends but suggests “nationally, the biggest growth probably related to biological factors is the increase in sleep apnoea. As a population we’ve become heavier and sleep apnoea has become increasingly common.

“But an increased awareness of sleep issues in general means more people are coming forward.”

He continues: “We see a broad range of conditions, from sleep apnoea and restless legs syndrome, extending to some of the more extreme conditions like narcolepsy, sleepwalking and those with Kleine-Levin, an excessive sleeping disorder referred to by some as ‘Sleeping Beauty syndrome’.”

Eating parrot feed

Dr Leschziner, who became the centre’s clinical lead for sleep in 2013, recounts the story of a man who would eat while asleep.

“He had cleared his entire fridge, eaten his pet parrot’s bird feed and woke himself up by spooning coffee grounds into his mouth. We know that this is a biological condition but it was also hugely influenced by psychological factors.”

Dr Leschziner also details the chilling case of a man who came to the clinic with a seemingly innocuous sleep-talking complaint that began shortly after he entered into a new relationship.

During his sleep, the man apparently started to talk about the sexual abuse of people around him.

Dr Leschziner continues: “The man bought some voice-activated recording equipment and was woken by his girlfriend screaming. But when he listened back, he was completely silent.”

It transpired that his girlfriend had mental health issues and had made it all up.

Deep enchantment with the brain

This story, along with many others, features in Dr Leschziner’s new book, The Nocturnal Brain: Nightmares, Neuroscience and the Secret World of Sleep.

It’s the result of a deep enchantment with the brain, which began during childhood. “I was fascinated by this mass of jelly that sits inside our heads; that influences who we are as individuals, our tastes, experiences, memories and consciousness,” he says.

Dr Leschziner, who studied at the University of Oxford and trained at Guy’s Hospital, says there is still much mystery over what happens to our brains during sleep.

“Sleep is a brilliant example of lots of things coalescing together,” he says. “It’s not only influenced by the electrical activity in our brain or the chemicals coursing through it, but our psychological state too. Feeling stressed, anxious or depressed can all influence sleep.”

Lifestyle factors

Dr Leschziner says lifestyle factors, such as drinking alcohol, smoking, or checking emails in bed, can also prevent a good night’s rest.

An estimated 30 per cent of Britons say they sleep poorly most nights of the week, a Sleep Council survey found, with laying in bed worrying, being disturbed by a partner and noisy environments among the top three reasons.

Dr Leschziner says we should trust our instincts and remove any obstacles that prevent us from sleeping well.

The Nocturnal Brain: Nightmares, Neuroscience and the Secret World of Sleep, by Dr Guy Leschziner, is out now.

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